Environmental and Ventilation Benefits for Underground Mining Operations Using Fuelcell Powered Production Equipment

CIM Montreal 2007
Stephen Hardcastle, Doug Eastick,
Abstract Charles Kocsis, Stephen Hardcastle, Doug Eastick

Over the last few years, with the support of mining operations, research laboratories, equipment manufacturers, universities and regulatory agencies, a number of research projects have been conducted to evaluate the feasibility of introducing fuelcell powered production equipment in mines. So far, environmentally, these studies have shown that fuelcell, as opposed to diesel, powered equipment could potentially be very beneficial in underground mines but to what degree is dependant upon a number of operational issues. The advantages range from, at the minimum, a better environment for the underground workforce and globally with the reduction of diesel combustion contaminants, through to potentially significant ventilation reductions. One notable health and safety benefit of the fuelcell technology would be the significant reduction of diesel particulate matter (DPM) generated by the production fleet. As a suspected carcinogen, DPM is subject to increasing scrutiny that could require mine operators to supply more ventilation., Fuelcell powered equipment also has the advantage of reduced noise and heat production compared to their equivalent diesel powered counterpart. In regard to mine ventilation, which can be a major cost item, fuelcells could reduce the mines overall demand for ventilation or permit more production per unit volume. However, increasing heat with depth and other mine specific qualifiers, such as inherent dust conditions, blast fume clearance and minimum air velocity limits can mitigate the potential ventilation benefits.

A major consideration in the introduction of fuelcells using hydrogen in underground operations is their safety considering the explosive nature of the fuel. Here, the effectiveness of a ventilation system in diluting and removing hydrogen and preventing the creation of an explosive gas atmosphere as a result of a hydrogen leak is dependant upon the availability of a sufficient air volume. In surface applications, where there is a significant interest in hydrogen fueled service vehicles, it is possible to use buoyancy, time, and lack of ignition sources as mitigating factors in deriving a low risk of an explosion. However, in underground operations these factors are changed, dispersion is limited by the confines of the drift/productions stope; buoyancy is also restricted by the back of the airway; time cannot be considered until the hydrogen is adequately diluted or removed from the mine; and the ignition sources (i.e. from electrical equipment) are not typically controlled in metal mines. Consequently, ventilation may be the prime risk controlling factor.

In this paper, the authors evaluate the potential benefits of replacing diesel engines with fuelcells in powered production equipment, discuss the mitigating qualifiers that could limit ventilation savings and evaluate solutions to retain and maintain an additional ventilation capacity in the event of an emergency situation such as a hydrogen leak from the fuelcell stack or its distribution system.
Keywords: Hydrogen fuel cells, ventilation requirements
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